Joseph Jeswin, Modenkattil Sethumadhavan Kavitha, Ahlawat Priyanca, Prakash Malavika, Kandpal Gayatri, Raj Gowtham, Srivastava Harshal, Charulekha Packirisamy, K Dev Aswin, Radhakrishnan Akshaya, Singh Virendra, Yadav Rahul, Chandramohanan Purnima, Varghese Reji, Rizvi Zaigham Abbas, Awasthi Amit, Raj V Stalin
Virology Scientific Research (VSR) Laboratory, School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram 695551, India.
Immuno-biology Laboratory, Translational Health Science & Technology Institute (THSTI), Faridabad 121001, India.
ACS Nano. 2025 Aug 12;19(31):28295-28314. doi: 10.1021/acsnano.5c06081. Epub 2025 Jul 31.
Lumazine synthase (LS), a bacterial protein that self-assembles into 60-mer icosahedral virus-like nanoparticles, has emerged as a promising platform for nanoparticle-based drug delivery and vaccine design. However, detailed biophysical characterization of the LS nanoparticle vaccine has not been well-studied. In this study, we generated LS nanoparticles fused with domain B of protein A (pA-LS), enabling their binding to the hFc-tagged S1 domain of the SARS-CoV-2 spike protein harboring two critical mutations (E484K and D614G) associated with increased infectivity and antibody escape. Biophysical analysis, such as transmission electron microscopy (TEM), revealed an extended size (∼45 nm) compared with the empty particle (∼15 nm). Similarly, atomic force microscopy (AFM) and dynamic light scattering (DLS) analyses confirmed increases in height and diameter. The spike-decorated nanoparticles demonstrated multivalent surface presentation by binding to the ACE2 receptor with a speckle-like appearance. Immunization of mice with pA-LS-S1-hFc elicited neutralizing antibodies against SARS-CoV-2 and its variants. Further, immunization followed by a live SARS-CoV-2 challenge (Wuhan-Hu-1, B.1.617.2 (Delta), or B.1.1.529 (Omicron)) in K18-hACE2 transgenic mice significantly reduced the lung viral load and pathology. Additionally, we generated mosaic nanoparticles displaying spike proteins from two epidemic coronaviruses, SARS-CoV-1 and MERS-CoV, which exhibited binding to their respective cellular receptors, ACE2 and DPP4, with similar binding patterns. Immunization with these mosaic nanoparticles elicited cross-reactive neutralizing antibodies against SARS-CoV-1 and MERS-CoV pseudoviruses. Our proof-of-concept data demonstrate the versatility of the LS nanoparticle platform for antigen presentation, supporting the development of multivalent vaccine designs targeting diverse antigens and contributing to immunogen design strategies.
鲁马嗪合酶（LS）是一种可自组装成60聚体二十面体病毒样纳米颗粒的细菌蛋白，已成为基于纳米颗粒的药物递送和疫苗设计的一个有前景的平台。然而，LS纳米颗粒疫苗的详细生物物理特性尚未得到充分研究。在本研究中，我们生成了与蛋白A的B结构域（pA-LS）融合的LS纳米颗粒，使其能够与携带两个与传染性增加和抗体逃逸相关的关键突变（E484K和D614G）的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）刺突蛋白的人Fc标签化S1结构域结合。生物物理分析，如透射电子显微镜（TEM）显示，与空颗粒（约15纳米）相比，其尺寸更大（约45纳米）。同样，原子力显微镜（AFM）和动态光散射（DLS）分析证实了高度和直径的增加。带有刺突蛋白的纳米颗粒通过与血管紧张素转换酶2（ACE2）受体结合呈现出斑点状外观，展示了多价表面呈现。用pA-LS-S1-hFc免疫小鼠可引发针对SARS-CoV-2及其变体的中和抗体。此外，在K18-hACE2转基因小鼠中，用活的SARS-CoV-2（武汉-Hu-1、B.1.617.2（德尔塔）或B.1.1.529（奥密克戎））攻击之前进行免疫，可显著降低肺部病毒载量和病理变化。此外，我们还生成了展示来自两种流行冠状病毒SARS-CoV-1和中东呼吸综合征冠状病毒（MERS-CoV）刺突蛋白的嵌合纳米颗粒，它们以类似的结合模式与各自的细胞受体ACE2和二肽基肽酶4（DPP4）结合。用这些嵌合纳米颗粒免疫可引发针对SARS-CoV-1和MERS-CoV假病毒的交叉反应中和抗体。我们的概念验证数据证明了LS纳米颗粒平台在抗原呈递方面的多功能性，支持了针对多种抗原的多价疫苗设计的开发，并为免疫原设计策略做出了贡献。
